Furnish services, qualified personnel, and material, equipment, and facilities, not otherwise provided by the Government uder the terms of the contract. Further purification and characterization of the PN-antigen using ion exchange chromatography and molecular sieving, isoelectric focussing, SDS-acrylamide electrophoresis, preparative gel electrophoresis, and affinity chromatography. Develop sensitive assay for PN-antigen with elaboration of the physical and chemical methods of the assay. Employ radioimmunoassay (RIA) to study the normal distribution of PN-antigen in liver, other tissues, and in blood of fetal, neonatal, and mature rats. Use RIA also to study PN-antigen distribution in carcinogen-induced lesions. Perform possible other blood studies depending upon the results of the above.